Maurodus arcus, Leschen & Reid & Nadein, 2020

Leschen, Richard A. B., Reid, Chris A. M. & Nadein, Konstantin S., 2020, Generic Review of New Zealand Chrysomelinae (Coleoptera: Chrysomelidae), Zootaxa 4740 (1), pp. 1-66 : 34

Maurodus arcus , sp. nov.

( Figs 4A,B ; map Fig. 19A )

Diagnosis. Body broadly ovate and bicoloured; pronotum bicoloured. Antennal groove not demarked by ridges. Prosternal lines in front of procoxae parallel. Elytra with midbasal stria present; maculae broad with outer edges sinuate and contacting broadly at midline; microsculpture strongly impressed. Ventrites dark-coloured and infuscate, with anterior portion of hypomera and entire epipleura pale-coloured; male ventrite 5 vaulted at middle. Legs bicoloured with femora and tibiae infuscate; tarsomere 1 of male greatly enlarged.

Description. Length 3.8 mm (greatest depth 1.6 mm). Body broadly oval and bicoloured with most of the head, most of the pronotum, elytral macula, and middle portions of the ventral surfaces black; extreme anterior margin of clypeus, margins of pronotum and elytra, mouthparts, antennae, anterior portion of the hypomera and epipleura, yellow-coloured; elytral maculae sinuate along lateral edge. Microsculpture distinct, present on pronotum and elytra. Clypeus finely punctate, semicircular, anterior margin nearly straight; frontoclypeal suture present with lateral postclypeal lines present and very weakly impressed and medial line indicated by a very faint glabrous area; vertex moderately punctate, slightly more coarse than clypeal punctures. Ratio of antennomere lengths: 1.5/0.9/1.3/1.0/1.0/1.2/1.2/1.0/1.2/1.3/1.9. Antennal groove not well demarked by ridges. Pronotum transverse (2.75 x wider than long), lateral margins at base not subparallel-sided and sides converging anteriorly, not strongly convex; punctures coarse at base and progressively shallower anteriorly, and somewhat uniform anteriorly, those at base stronger than elsewhere on the dorsum, apart from the latero-apical striae of the elytra. Prosternal lines or carinae in front of procoxae parallel; intercarinal space flat. Elytra widest at basal 1/3 and broad (1.07x the greatest elytral width), 3.75x longer than pronotal length; punctation weakly striate, not impressed towards midline; midbasal stria present. Male ventrite 5 vaulted at middle. Tarsomere 1 of male greatly enlarged.

Comments. This species is represented by a single male specimen collected by sifting tussock litter at Rainbow Ski Field where access is granted with permission. Maurodus arcus can be distinguished from most species of the genus by the presence of a process or vaulted abdominal ventrite 5 in the male, which is shared with M. maculatus and can be distinguished from it based on the shape of the body where the elytra are widest at the basal 1/3, the elytral macula broadly contacts the anterior margin of the elytra, and the hypomeron is bicoloured. Maurodus arcus can be further differentiated from M. maculatus by the head which is not infuscate with only the anteriormost edge of the clypeus yellow-coloured and the vaulted medial process of the male is more strongly produced.

Distribution. South Island: NN.

Etymology. The specific epithet is derived from the Latin word arcus one meaning of which is “rainbow”, referring to the type locality of this new species.

Type examined. Holotype ( NZAC): “ NEW ZEALAND MB Rainbow Ski Field Rd below ski field St Arnaud Ra 26 Feb 2010 TR Buckley R Leschen L Dunning // TB339 sifting tussock litter 41 52.790 S, 172 51.572 E, 1456m ”.

Figures

FIGURES 4A–F. Habitus of Maurodus spp.; A, Maurodus arcus, dorsal; B, Maurodus arcus, lateral; C, Maurodus cinctiger, dorsal, length 4.1 mm; D, Maurodus cinctiger, lateral, length 4.2 mm; E, Maurodus cinctiger, dorsal; F, Maurodus cinctiger, ventral.

FIGURES 19A–B. A and B, South Island.